This invention relates generally to imaging systems, and more particularly, to methods and systems for assessing gross patient movement in diagnostic imaging, especially in a PET-CT imaging.
Patient motion during a positron emission tomography (PET)-computed tomography (CT) scan may be undetected and may affect the diagnostic quality of a PET-CT scan. The motion may be both voluntary (e.g., head turn, hand movement, speaking and the like) or involuntary (e.g., breathing). Typically, a technologist may not be able to constantly monitor a patient to ensure the patient remains motionless for the period of time required for a PET scan (e.g., 20-30 minutes or more). In addition, some patients have certain physical conditions causing them difficulty in remaining still or remaining in a particular position for any length of time (e.g., pain resulting from being placed in one position for any length of time, involuntary movements from a disease such as Parkinson's disease, or, for instance, any type of kinesis, and the like). In addition, some positions, which may be advantageous for scanning, may be difficult for the patient to maintain for long durations (e.g., arms above the head).
Once motion is detected, a technologist may decide to re-scan the patient, re-prescribe a CT attenuation scan to apply to the post-motion patient position, or ensure the patient is comfortable for the remainder of the scan session, among other actions. Correcting for motion during a scan takes time and resources. Any motion caused by the patient moving during a scan decreases the quality of the images. For instance, any motion may cause the images to be blurred. Therefore, being able to monitor when a patient moves during the scan is desirable in order to improve the diagnostic quality of a PET-CT scan and reduce image time by decreasing the need for re-scans, and the like.
What is needed is method and system to automatically assess gross patient motion, such as movement of the arm position during scanning, while a patient is undergoing a scan and a radioactive tracer remains in situ. Further, the ability to detect whether a patient has moved during a scan that allows a quality of data to be addressed in real-time as well as allow for a post-scan quality assurance is needed.